Both experimental and clinical studies have demonstrated the potential adverse effect of sympathoexcitation in high risk patients with ischemia heart disease, as well as the potential for cardioprotection by programmed vagal activity. General vagal stimulation of the entire vagus nerve tends to decrease heart rate, lower respiration, and lower blood pressure.
Vagal afferent nerve stimulation through central medullary pathways increases cardiac vagal modulation to provide the benefits of central cardioinhibition, without adversely affecting heart rate, respiration or hemodynamics. However, typical closed-loop feedback control for vagal afferent nerve stimulation is difficult if the vagal afferent nerve stimulation does not have a significant effect on heart rate, respiration, or hemodynamics.